The present disclosure is directed to an ultrasonic motor.
Conventionally, various ultrasonic motors which vibrate a stator by a piezoelectric device have been proposed. Japanese Unexamined Patent Application Publication No. 2001-054288 (the “'288 Publication”) discloses one example of an ultrasonic motor. In this ultrasonic motor, a disc spring presses a rotor to bring the rotor and the stator to contact closely. A collar is assembled to the center of the rotor. The collar includes a plurality of convex portions, whereas the disc spring includes a plurality of concave portions. The plurality of convex portions of the collar and the plurality of concave portions of the disc spring mate with each other, and the disc spring is positioned. In this manner, pressure is attempted to be applied to the rotor and the stator uniformly in a circumferential direction. Moreover, the rotor is fixed to a rotating shaft with the collar interposed therebetween.
In the ultrasonic motor of the '288 Publication, the rotating shaft, the rotor, the collar, and the disc spring are complexly combined together. However, when stress caused by vibration or heat is continuously applied during long-term use, loosening may be caused at a portion where the members closely contact with each other, which may cause misalignment, for example, between the rotating shaft and the disc spring. Therefore, abnormal noise may be caused due to contact between the members.
According to an aspect of the disclosure is to provide an ultrasonic motor which is less likely to cause misalignment between a spring member and a shaft member.
An ultrasonic motor according to the present disclosure includes: a stator including a vibrating body in a plate shape having a first principal surface and a second principal surface opposed to each other, and including a piezoelectric device provided on the first principal surface of the vibrating body; a rotor directly or indirectly in contact with the second principal surface of the vibrating body; a spring member in a plate shape having an opening and configured to give elastic force to the rotor in a direction from a side of the rotor to a side of the stator; and a shaft member inserted into the opening of the spring member and having a mating portion. A shape of the opening of the spring member is a noncircular shape in a plan view. The spring member has a convex portion bent in a direction from the side of the stator to the side of the rotor, and an opening edge portion of the opening mates with the mating portion of the shaft member, the opening edge portion being a tip-end portion of the convex portion.
According to the ultrasonic motor of the present disclosure, misalignment is less likely to be caused between the spring member and the shaft member.
In the descriptions that follow, like parts are marked throughout the specification and drawings with the same numerals, respectively. The drawings are not necessarily drawn to scale and certain drawings may be shown in exaggerated or generalized form in the interest of clarity and conciseness. The disclosure itself, however, as well as a mode of use, further features and advances thereof, will be understood by reference to the following detailed description of illustrative implementations of the disclosure when read in conjunction with reference to the accompanying drawings, wherein:
Hereinbelow, aspects of the present disclosure will be described. In a following description of the drawings, the same or similar components will be represented with use of the same or similar reference characters. The drawings are exemplary, sizes or shapes of portions are schematic, and technical scope of the present disclosure should not be understood with limitation to the aspects.
It is noted that the aspects described herein are merely illustration, and partial replacement or combination of configurations is possible between different aspects.
As illustrated in
As illustrated in
Herein, a direction viewed in the axial direction Z may be referred to as plan view or bottom view. Note that plan view is a direction viewed from above and bottom view is a direction viewed from below in
AS illustrated in
The spring member 6 gives elastic force to the rotor 4 through an elastic member 5. Note that the elastic member 5 does not have to be provided.
The spring member 6 includes an opening 6c at a center portion thereof. A convex portion 6d is provided to surround the opening 6c. The convex portion 6d is a portion bent in a direction from the stator 2 side to the rotor 4 side, in the spring member 6. More specifically, the convex portion 6d has a conical shape. A tip-end portion 6e of the convex portion 6d is an opening edge portion of the opening 6c.
The opening 6c of the spring member 6 has a hexagonal shape in plan view. Slit portions 6g extend in the convex portion 6d from the respective vertex portions of the hexagonal shape of the opening 6c. Note that the slit portions 6g do not have to be provided to the convex portion 6d. The shape of the opening 6c is not limited to the shape described above as long as it has a noncircular shape in plan view. The noncircular shape indicates, for example, a polygonal shape, an oval shape, a shape in which a curved line and a straight line are connected together, or a shape in which a curved line and a curved line are connected together.
The spring member 6 includes a plurality of beam portions 6f. The plurality of beam portions 6f are arranged radially in plan view. Elastic force caused by displacement of the plurality of beam portions 6f is given to the rotor 4. Note that the plurality of beam portions 6f do not have to be provided. The spring member 6 may have, for example, a circular shape or a regular polygonal shape in plan view.
As illustrated in
Features of this aspect are that the shape of the opening 6c of the spring member 6 has a noncircular shape when viewed in the axial direction Z, the convex portion 6d projects in the direction from the stator 2 side to the rotor 4 side, and the tip-end portion 6e of the convex portion 6d mates with the mating portion 7a of the shaft member 7. Therefore, misalignment is less likely to be caused between the spring member 6 and the shaft member 7.
More specifically, since the opening 6c has a noncircular shape, misalignment in a circling direction is less likely to be caused between the spring member 6 and the shaft member 7. Moreover, by elastic force being given from the spring member 6 to the rotor 4, reaction force is applied to the spring member 6 from the rotor 4 side. Here, the direction in which the convex portion 6d of the spring member 6 projects is opposite from the direction in which the elastic force is given to the rotor 4. That is, the convex portion 6d projects in the direction in which the reaction force is applied to the spring member 6. Therefore, the tip-end portion 6e of the convex portion 6d is pushed against the mating portion 7a of the shaft member 7. In this manner, the force may be given all the time such that the spring member 6 and the shaft member 7 integrate with each other. Thus, even when the ultrasonic motor 1 is used over a long period of time and its members wear, loosening is less likely to be caused at the portion where the spring member 6 and the shaft member 7 mate with each other. As a result, misalignment is less likely to be caused between the spring member 6 and the shaft member 7.
As illustrated in
The first case member 8 has a first cylindrically projecting portion 8a and a second cylindrically projecting portion 8b. The first cylindrically projecting portion 8a projects outside the case. The second cylindrically projecting portion 8b projects inside the case. The second cylindrically projecting portion 8b is inserted into the through hole 3c of the vibrating body 3 of the stator 2.
A through hole 8c is continuously provided to the first cylindrically projecting portion 8a and the second cylindrically projecting portion 8b. A width of the through hole 8c at a portion located at the first cylindrically projecting portion 8a is larger than a width of the through hole 8c at a portion located at the second cylindrically projecting portion 8b. Herein, unless particularly noted, a width of a through hole or an opening is a dimension of the through hole or the opening in a direction orthogonal to the axial direction Z. A first bearing part 18 is provided inside the through hole 8c at the portion located at the first cylindrically projecting portion 8a. The shaft member 7 is inserted into the through hole 8c and the first bearing part 18. The shaft member 7 projects outside the case from the through hole 8c of the first case member 8. Note that the configuration of the first case member 8 is not limited to the above.
The second case member 9 has a cylindrically projecting portion 9a. The cylindrically projecting portion 9a projects outside the case. The cylindrically projecting portion 9a includes a through hole 9c. A second bearing part 19 is provided inside the through hole 9c. The shaft member 7 is inserted into the through hole 9c and the second bearing part 19. The shaft member 7 projects outside the case from the through hole 9c of the second case member 9. Note that the configuration of the second case member 9 is not limited to the above. Bearings or the like may be used as the first bearing part 18 and the second bearing part 19, for example.
As illustrated in
Friction material may be fixed to a surface of the rotor 4 on the stator 2 side. Thus, frictional force caused between the vibrating body 3 of the stator 2 and the rotor 4 can be stabilized. In this case, the rotor 4 can effectively be rotated, and the ultrasonic motor 1 can effectively be rotationally driven.
A plurality of protrusions 3d are provided on the second principal surface 3b of the vibrating body 3. The plurality of protrusions 3d are portions in contact with the rotor 4, in the vibrating body 3. Each protrusion 3d protrudes from the second principal surface 3b of the vibrating body 3 in the axial direction Z. The plurality of protrusions 3d are arranged in a circular ring shape when viewed in the axial direction Z. Since the plurality of protrusions 3d protrude from the second principal surface 3b in the axial direction Z, tip ends of the plurality of protrusions 3d are displaced further largely when a traveling wave is generated in the vibrating body 3. Therefore, the rotor 4 can effectively be rotated by the traveling wave generated in the stator 2. Note that the plurality of protrusions 3d do not have to be provided.
A plurality of piezoelectric devices are provided to the first principal surface 3a of the vibrating body 3. More specifically, the plurality of piezoelectric devices are a first piezoelectric device 13A, a second piezoelectric device 13B, a third piezoelectric device 13C, and a fourth piezoelectric device 13D. In order to generate a traveling wave which circles centering on an axis parallel to the axial direction Z, the plurality of piezoelectric devices are dispersedly arranged in a circling direction of the traveling wave. When viewed in the axial direction Z, the first piezoelectric device 13A and the third piezoelectric device 13C are opposed to each other with the axis therebetween. The second piezoelectric device 13B and the fourth piezoelectric device 13D are opposed to each other with the axis therebetween.
The first piezoelectric device 13A includes a piezoelectric material 14. The piezoelectric material 14 has a third principal surface 14a and a fourth principal surface 14b. The third principal surface 14a and the fourth principal surface 14b are opposed to each other. The first piezoelectric device 13A includes a first electrode 15A and a second electrode 15B. The first electrode 15A is provided on the third principal surface 14a of the piezoelectric material 14, and the second electrode 15B is provided on the fourth principal surface 14b. The second piezoelectric device 13B, the third piezoelectric device 13C, and the fourth piezoelectric device 13D are also configured similarly to the first piezoelectric device 13A. Each piezoelectric device has a rectangular shape in plan view. Note that the shape of the piezoelectric device in plan view is not limited to the shape described above and may be an oval shape, for example. Here, the first electrode 15A is attached to the first principal surface 3a of the vibrating body 3 by adhesive. A thickness of the adhesive is extremely thin. Therefore, the first electrode 15A is electrically connected to the vibrating body 3.
Note, in order to generate a traveling wave, it is sufficient that the stator 2 includes at least the first piezoelectric device 13A and the second piezoelectric device 13B. Alternatively, the stator 2 may include a single piezoelectric device divided into a plurality of ranges. In this case, for example, the respective ranges of the piezoelectric device may be polarized in directions different from each other.
A structure of the stator 2 to generate a traveling wave by the plurality of piezoelectric devices being dispersedly arranged in a circling direction and being driven is disclosed in WO2010/061508A1, for example. Note that, in terms of the structure to generate the traveling wave, in addition to the following description, a configuration described in WO2010/061508A1 is hereby incorporated in its entirety.
In
Note that A+, A−, B+, and B− in
Note that although the example where the wavenumber is three is described, it is not limited to this. Also in a case where the wavenumber is six, nine, twelve, or the like, two standing waves having a phase difference at 90° are similarly excited, and by the two standing waves being synthesized, a traveling wave is generated. In the present disclosure, the configuration to generate a traveling wave is not limited to the configuration illustrated in
As illustrated in
In this aspect, a shape of the shaft member 7 at the portion inserted into the rotor 4 is a cylindrical shape. A shape of the through hole 4c of the rotor 4 when viewed in the axial direction Z is circle. Note that the shape of the above-mentioned portion of the shaft member 7 and the shape of the through hole 4c of the rotor 4 are not limited to the shapes described above.
A Young's modulus of the spring member 6 is preferably higher than a Young's modulus of the shaft member 7. Alternatively, a Vickers hardness of the spring member 6 is preferably higher than a Vickers hardness of the shaft member 7. In this aspect, the tip-end portion 6e of the convex portion 6d of the spring member 6 is positioned in the groove portion 7b of the shaft member 7. As a result of having the relation in terms of the Young's modulus or the Vickers hardness described above, the tip-end portion 6e of the convex portion 6d can further bite into the shaft member 7. Thus, the spring member 6 and the shaft member 7 can further firmly mate with each other. Accordingly, misalignment is further less likely to be caused between the spring member 6 and the shaft member 7.
Moreover, in the case of having the relation in terms of the Young's modulus or the Vickers hardness described above, the groove portion 7b does not have to be provided to the mating portion 7a of the shaft member 7 in advance. Since the tip-end portion 6e of the convex portion 6d of the spring member 6 is harder than the shaft member 7, the tip-end portion 6e bites into the mating portion 7a of the shaft member 7. More specifically, when the spring member 6 and the shaft member 7 mate with each other, the spring member 6 is displaced as illustrated in
As material of the spring member 6, for example, stainless spring material (for example, SUS304-CSP and SUS301CSP-H), phosphor bronze, nickel silver, or the like may be used. As material of the shaft member 7, for example, SUS430, aluminum, brass, resin, or the like may be used. In these cases, the relation that the Young's modulus of the spring member 6 is higher than the Young's modulus of the shaft member 7 can be satisfied. Moreover, for example, when SUS430 is used as the material of the shaft member 7, the Vickers hardness is 200 HV or lower, and when SUS301CSP-H is used as the material of the spring member 6, the Vickers hardness is 430 HV or higher. In this manner, the relation that the Vickers hardness of the spring member 6 is higher than the Vickers hardness of the shaft member 7 can be satisfied. Thus, since the groove portion does not have to be provided to the mating portion 7a of the shaft member 7 in advance as described above, productivity can be improved.
When a dimension of the shaft member 7 in the direction orthogonal to the axial direction Z is a width of the shaft member 7, the width of the opening 6c of the spring member 6 in the state where the spring member 6 and the shaft member 7 do not mate with each other is preferably smaller than a width of the mating portion 7a of the shaft member 7 at a portion not including the groove portion 7b. Therefore, when the spring member 6 and the shaft member 7 are mated with each other, the tip-end portion 6e of the convex portion 6d of the spring member 6 can further strongly be pushed against the mating portion 7a of the shaft member 7. Thus, the spring member 6 and the shaft member 7 can further firmly be mated with each other.
Note that the width of the opening 6c changes accompanying with the displacement of the spring member 6. As described above, since the width of the opening 6c changes, the shaft member 7 can be inserted into the opening 6c even when the width of the opening 6c is small. By the spring member 6 being displaced as illustrated in
The shape of the opening 6c of the spring member 6 is preferably a polygonal shape when viewed in the axial direction Z. Moreover, the shape of the mating portion 7a of the shaft member 7 is preferably a polygonal shape when viewed in the axial direction Z. The shape of the opening 6c of the spring member 6 and the shape of the mating portion 7a of the shaft member 7 when viewed in the axial direction Z are preferably polygonal shapes having the same number of vertexes. Accordingly, the spring member 6 and the shaft member 7 can be made to contact with each other at sides of the polygonal shapes. Thus, misalignment in the circling direction is further less likely to be caused between the spring member 6 and the shaft member 7.
In one aspect of the disclosure, the spring member 6 and the shaft member 7 directly mate with each other without intervention of another member. Therefore, the number of components can be reduced, and cost reduction is possible.
In addition, the spring member 6 contacts the shaft member 7 at the tip-end portion 6e of the convex portion 6d. Therefore, a contact area between the spring member 6 and the shaft member 7 is small. Thus, vibration of the rotor 4 is further less likely to be propagated to the shaft member 7. As a result, the ultrasonic motor 1 can further stably be driven.
The convex portion 6d of the spring member 6 preferably includes the plurality of slit portions 6g. In this case, the convex portion 6d can easily be formed in a manufacturing process, which improves productivity.
When the plurality of slit portions 6g are provided, the convex portion 6d has a plurality of tip-end portions 6e. In this case, the mating portion 7a of the shaft member 7 preferably includes a plurality of groove portions 7b. Preferably, the plurality of groove portions 7b are dispersedly arranged in the circling direction and each groove portion 7b mates with the corresponding tip-end portion 6e. In this case, each tip-end portion 6e can be embedded into the shaft member 7, and therefore, each tip-end portion 6e is less likely to move in the circling direction. Thus, misalignment is further less likely to be caused between the spring member 6 and the shaft member 7.
The spring member 6 preferably includes the plurality of beam portions 6f. Therefore, displacement of the spring member 6 can easily be made larger. Thus, elastic force given to the rotor 4 by the spring member 6 may easily and more certainly be increased. As a result, the rotor 4 and the stator 2 may more certainly be made in close contact with each other, and the ultrasonic motor 1 may more certainly and effectively be driven.
The plurality of beam portions 6f are preferably arranged evenly in the circling direction. Therefore, the elastic force given to the rotor 4 can be made uniform in the circling direction. Thus, the ultrasonic motor 1 can stably be driven.
Further, the number of plurality of beam portions 6f is not an integral multiple of a wavenumber of a traveling wave and is a prime number. More specifically, a traveling wave with a wavenumber of three is utilized. In another aspect, the number of beam portions 6f is seven. Therefore, the spring member 6 is less likely to vibrate. Thus, vibration is less likely to be propagated to the shaft member 7, and the ultrasonic motor 1 can further stably be driven. In addition, occurrence of abnormal noise due to vibration of the spring member 6 can be suppressed.
A shape of a portion between the beam portions 6f of the spring member 6 when viewed in the axial direction Z is a curved shape. Therefore, concentration of stress is less likely to occur, and damage of the spring member 6 is less likely to be caused. Note that the shape of the spring member 6 is not limited to the shape described above. For example, the spring member 6 does not have to include the beam portion 6f.
The elastic member 5 is preferably provided between the spring member 6 and the rotor 4. Therefore, vibration of the rotor 4 is absorbed by the elastic member 5. Thus, vibration of the rotor 4 is less likely to be propagated to the spring member 6 and the shaft member 7. As a result, the ultrasonic motor 1 can stably be driven. As material of the elastic member 5, for example, rubber, resin, or the like may be used.
As illustrated in
The spring member 6 is in contact with the inner circumferential edge portion 5a of the elastic member 5. Moreover, the outer circumferential edge portion 6h of the spring member 6 is not in contact with the elastic member 5. Therefore, a contact area between the spring member 6 and the elastic member 5 can be made smaller. Thus, vibration from the rotor 4 side is less likely to be propagated to the spring member 6 and the shaft member 7. As a result, the ultrasonic motor 1 can further stably be driven.
First to fourth modifications of one aspect of the disclosure in which a configuration of a spring member, a piezoelectric device, a shaft member, or the like is different from that in other aspects are described below. In each modification, similarly to the one aspect, misalignment is less likely to be caused between the spring member and the shaft member.
In the first modification illustrated in
The second modification illustrated in
In the third modification illustrated in
A piezoelectric material of the piezoelectric device 23 is polarized to be opposite polarization directions in the first A-phase range and the second A-phase range. Similarly, the piezoelectric material of the piezoelectric device 23 is polarized to be opposite polarization directions in the first B-phase range and the second B-phase range. That is, the piezoelectric device 23 is a piezoelectric device polarized into plural.
The piezoelectric device 23 includes a plurality of first electrodes 15A indicated by a one-dot chain line. Each first electrode 15A has an arc shape. The first electrodes 15A provided to the ranges adjacent to each other in the piezoelectric device 23 are not in contact with each other. Therefore, signals in phases which are different between the plurality of first and second A-phase ranges and the plurality of first and second B-phase ranges can be supplied. Note that a second electrode is provided to be opposed to the first electrode 15A with the piezoelectric material therebetween. A plurality of second electrodes may be provided similarly to the plurality of first electrodes 15A, or a single second electrode in a circular ring shape may be provided.
The fourth modification illustrated in
In one aspect of the disclosure, the width of the opening 6c of the spring member 6 and a configuration of a shaft member 37 are different from those in the one aspect. Configurations of an ultrasonic motor of this aspect other than the above points are similar to the configurations of the ultrasonic motor 1 of the one aspect.
A mating portion 37a of the shaft member 37 does not have a groove portion. The mating portion 37a has a protruding portion 37e. The protruding portion 37e projects in a direction orthogonal to the axial direction Z over the entire circling direction. The tip-end portion 6e of the convex portion 6d of the spring member 6 is in contact with the protruding portion 37e. Therefore, the spring member 6 and the shaft member 37 mate with each other. Note that the width of the opening 6c of the spring member 6 is the same as a width of the mating portion 37a of the shaft member 37 at a portion not including the protruding portion 37e.
Also in this aspect, the direction in which the convex portion 6d of the spring member 6 projects is opposite from the direction in which elastic force is given to the rotor 4. That is, the convex portion 6d projects in the direction in which reaction force is applied to the spring member 6 from the rotor 4 side. Therefore, the tip-end portion 6e of the convex portion 6d is pushed against the mating portion 37a of the shaft member 37. Thus, long-term use is less likely to cause loosening at the portion where the spring member 6 and the shaft member 37 mate with each other. As a result, similarly to the one aspect, misalignment is less likely to be caused between the spring member 6 and the shaft member 37.
The mating portion 37a of the shaft member 37 may have both of the groove portion and the protruding portion 37e. Similarly to the one aspect, the tip-end portion 6e of the convex portion 6d of the spring member 6 may be positioned in the groove portion. A portion of the convex portion 6d other than the tip-end portion 6e may be in contact with the protruding portion 37e. Also in this case, misalignment is less likely to be caused between the spring member 6 and the shaft member 37.
Meanwhile, the shape of the rotor 4 illustrated in
In a sixth modification of the one aspect illustrated in
Note that the frame portion 26j may be provided not to the first surface 26a but to the second surface 26b. Alternatively, the frame portion 26j may be provided integrally with the plurality of beam portions 6f. The frame portion 26j does not have to reach the outer circumferential edge portion 6h of each beam portion 6f, as long as the frame portion 26j connects the beam portions 6f together. A shape of an outer circumferential edge of the frame portion 26j is not limited to a circular shape and may be a noncircular shape. Similarly, a shape of an inner circumferential edge of the frame portion 26j is not limited to a circular shape and may be a noncircular shape.
In a seventh modification of the one aspect illustrated in
Note that the plurality of wide portions 26k may be provided not to the first surface 26a but to the second surface 26b. Alternatively, the wide portion 26k may be provided integrally with the beam portion 6f. The wide portion 26k does not have to reach the outer circumferential edge portion 6h of the beam portion 6f. The shape of the wide portion 26k is not limited to the rectangular shape and may be, for example, a circular shape, or a noncircular shape other than the rectangular shape. The wide portion 26k in this modification and the frame portion 26j in the sixth modification are applicable to the configurations of the present disclosure.
In accordance with aspects of the disclosure described above, the tip end of the convex portion 6d of the spring member 6 has a planar shape. As illustrated in, for example,
In one aspect of the disclosure, a tip end of a convex portion 46d of a spring member 46 has a curved surface. Configurations of an ultrasonic motor of this aspect other than the above point are similar to the configurations of the ultrasonic motor of other aspects.
In accordance with aspects of the disclosure, a tip-end portion 46e of the convex portion 46d of the spring member 46 is in contact with the protruding portion 37e of the shaft member 37. Therefore, the spring member 46 and the shaft member 37 mate with each other. Then, by reaction force being applied to the spring member 46 from the rotor 4 side, the tip-end portion 46e is pushed against the protruding portion 37e. Therefore, loosening is less likely to be caused at the portion where the spring member 46 and the shaft member 37 mate with each other. As a result, misalignment is less likely to be caused between the spring member 46 and the shaft member 37.
Moreover, the tip-end portion 46e of the convex portion 46d has a curved surface. Therefore, as illustrated in
In the configuration, the spring member 46 and the shaft member 37 preferably have at least one of relation that a Young's modulus of the spring member 46 is lower than a Young's modulus of the shaft member 37 and relation that a Vickers hardness of the spring member 46 is lower than a Vickers hardness of the shaft member 37. In this case, the tip-end portion 46e of the spring member 46 is less likely to bite into the shaft member 37. Therefore, the tip-end portion 46e may more certainly be slid on the surface of the mating portion 37a of the shaft member 37. As a result, positioning of the spring member 46 may further certainly be performed. Note that, for example, when SUS430 is used as material of the shaft member 37, C5191-1/2H (phosphor bronze type 2), C7521-1/2H (nickel silver type 2), or the like may be used as material of the spring member 46. In these cases, the Vickers hardness of the spring member 46 is lower than the Vickers hardness of the shaft member 37. Note that it is also possible that the Young's modulus of the spring member 46 is higher than the Young's modulus of the shaft member 37 and the Vickers hardness of the spring member 46 is higher than the Vickers hardness of the shaft member 37.
As illustrated in
For example, as illustrated in
Moreover, in this modification, the tip-end portion 56e of the spring member 56 including the curved surface can easily be formed by press punching processing. Thus, productivity can be improved.
In accordance with an aspect of the disclosure, a portion including a tip-end portion 66e of a convex portion 66d of a spring member 66 includes a folding portion 66l. Further, a bent portion of the folding portion 66l is the tip-end portion 66e of the convex portion 66d. Configurations of an ultrasonic motor of this aspect other than the above points are similar to the configurations of the ultrasonic motor described above.
In the folding portion 66l, a portion where the first surfaces 26a are opposed to each other is positioned on the inside. A portion of the second surface 26b of the tip-end portion 66e of the convex portion 66d is in contact with the shaft member 37. Further, the tip-end portion 66e has a curved surface. Therefore, positioning of the spring member 66 may more certainly be performed. In addition, misalignment is less likely to be caused between the spring member 66 and the shaft member 37.
The folding portion 66l includes a first portion 66m and a second portion 66n. The first portion 66m and the second portion 66n are connected to each other at the bent portion of the folding portion 66l. The first portion 66m is a portion on a proximal end side of the convex portion 66d. In a section parallel to the axial direction Z and passing through the center of the shaft member 37, assuming that an angle formed between an extension line C1 of the first portion 66m and an extension line C2 of the second portion 66l is θ, in this aspect, θ=0° holds. In other words, a bending angle of the folding portion 66l is 180°. Note that the angle θ is not limited to 0°. The angle θ is preferably equal to or smaller than an angle formed between the extension line C1 of the first portion 66m and a plane orthogonal to the axial direction Z. Therefore, the tip-end portion 66e of the convex portion 66d can easily be brought into contact with the protruding portion 37e of the shaft member 37.
In this aspect, a width of a mating portion 77a of a shaft member 77 at a portion other than the protruding portion 37e is smaller than a width of the shaft member 77 at a portion other than the mating portion 77a. Configurations of an ultrasonic motor of this aspect other than the above point are similar to the configurations of the ultrasonic motor described above. Note that the portion of the mating portion 77a other than the protruding portion 37e has a hexagonal prism shape.
Further, positioning of the spring member 46 may more certainly be performed. In addition, misalignment is less likely to be caused between the spring member 46 and the shaft member 37. Moreover, the protruding portion 37e can be formed at the same time as forming the mating portion 77a, thus processing being easier. As a result, productivity can be improved.
In general, the description of the aspects disclosed should be considered as being illustrative in all respects and not being restrictive. The scope of the present disclosure is shown by the claims rather than by the above description, and is intended to include meanings equivalent to the claims and all changes in the scope. While preferred aspects of the invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the invention.
Number | Date | Country | Kind |
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2021-023230 | Feb 2021 | JP | national |
This application is a continuation of International Application No. PCT/JP2022/003140, filed Jan. 27, 2022, which claims priority to Japanese Patent Application No. 2021-023230, filed Feb. 17, 2021, the entire contents of each of which are hereby incorporated by reference in their entirety.
Number | Date | Country | |
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Parent | PCT/JP2022/003140 | Jan 2022 | US |
Child | 18358436 | US |